UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post

regenfreak · 29th Jan 2019, 2:56 pm

Brilliant Dave! Mine failed. I used two new 2N5245 and identical components as the 73 magazine. I connected it to an unkown transistor IF can and used 9v. There was no oscillation.Then I increased from 9V to 18V, it burnt out both FETs.

Well I will have to try again.

I used to build many tesla coils and I built this 555 oscillator circuit which can determine the resonance frequency of a LC tank circuit:

https://www.rmcybernetics.com/scienc...sla-coil-tuner

I have tried it with a transistor IF can with a scope ( It can work reliably without scope). It works OK with IF cans but would not be as easy as the 73 magazine circuit. Sometimes the peaking is not that sharp depending on the Q etc..

Also the frequency sweeping with function generator and scope technique is rather time consuming..

29th Jan 2019, 2:56 pm	#2
regenfreak Heptode Join Date: Nov 2018 Location: London SW16, UK. Posts: 655	Re: IFT Checker Brilliant Dave! Mine failed. I used two new 2N5245 and identical components as the 73 magazine. I connected it to an unkown transistor IF can and used 9v. There was no oscillation.Then I increased from 9V to 18V, it burnt out both FETs. Well I will have to try again. I used to build many tesla coils and I built this 555 oscillator circuit which can determine the resonance frequency of a LC tank circuit: https://www.rmcybernetics.com/scienc...sla-coil-tuner I have tried it with a transistor IF can with a scope ( It can work reliably without scope). It works OK with IF cans but would not be as easy as the 73 magazine circuit. Sometimes the peaking is not that sharp depending on the Q etc.. Also the frequency sweeping with function generator and scope technique is rather time consuming.. Last edited by regenfreak; 29th Jan 2019 at 3:02 pm.